{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T16:26:20Z","timestamp":1792772780932,"version":"4.5.0"},"reference-count":22,"publisher":"Oxford University Press (OUP)","issue":"11","license":[{"start":{"date-parts":[[2026,10,16]],"date-time":"2026-10-16T00:00:00Z","timestamp":1792108800000},"content-version":"vor","delay-in-days":9,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"AstraZeneca US Medical Affairs"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,10,7]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Circulating tumor DNA (ctDNA) is an emerging tool in precision oncology that enables noninvasive tumor profiling, detection of minimal residual disease, and treatment monitoring. Furthermore, routine ctDNA analyses offer the potential to support more personalized and dynamic cancer care. In advanced breast cancer (aBC), ctDNA-based monitoring has been investigated across multiple studies as a tool for detecting emerging resistance mechanisms, predicting treatment responses and informing biomarker-guided treatment decisions. One example, investigated in the phase III PADA-1 and SERENA-6 trials, is monitoring for emergent estrogen receptor alpha mutations (ESR1m) during first-line endocrine therapy in estrogen-receptor positive, human epidermal growth factor receptor 2-negative (ER+, HER2\u2013) aBC. While not yet widely adopted in clinical practice, broader implementation of routine ctDNA-based monitoring for ESR1m is anticipated and will require standardized diagnostic workflows, encompassing both institutional operational processes and patient-centered scheduling pathways. Insights and recommendations were gathered from multidisciplinary experts across academic and community practices in the United States regarding the feasibility, barriers, and operational requirements for implementing ESR1m monitoring during first-line treatment of aBC. Here, we present practical, experience-informed considerations, supplemented by an opinion-based consensus workflow model designed to provide clinicians with a flexible framework for implementing ctDNA-based ESR1m monitoring during first-line care for ER+, HER2\u2013 aBC.<\/jats:p>","DOI":"10.1093\/oncolo\/oyag411","type":"journal-article","created":{"date-parts":[[2026,10,16]],"date-time":"2026-10-16T09:51:57Z","timestamp":1792144317000},"source":"Crossref","is-referenced-by-count":0,"title":["Integrating ctDNA-based\n                    <i>ESR1<\/i>\n                    m monitoring into first-line care for ER+, HER2\u2212 advanced breast cancer: a consensus workflow"],"prefix":"10.1093","volume":"31","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4827-8613","authenticated-orcid":false,"given":"Yara","family":"Abdou","sequence":"first","affiliation":[{"name":"Lineberger Comprehensive Cancer Center, UNC School of Medicine, University of North Carolina at Chapel Hill , Chapel Hill, NC 27599,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3596-0581","authenticated-orcid":false,"given":"Amber","family":"Cipriani","sequence":"additional","affiliation":[{"name":"Department of Pharmacy, UNC Health Medical Center , Chapel Hill, NC 27514,","place":["United States"]},{"name":"UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill , Chapel Hill, NC 27599,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Trevor","family":"Feinstein","sequence":"additional","affiliation":[{"name":"Piedmont Cancer Institute , Fayetteville, GA 30214,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ryan","family":"Haumschild","sequence":"additional","affiliation":[{"name":"Winship Cancer Institute, Emory University , Atlanta, GA 30322,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mabel","family":"Mardones","sequence":"additional","affiliation":[{"name":"Sarah Cannon Research Institute , Denver, CO 80218,","place":["United States"]},{"name":"Rocky Mountain Cancer Centers , Aurora, CO 80012,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2935-1934","authenticated-orcid":false,"given":"Joanne","family":"Mortimer","sequence":"additional","affiliation":[{"name":"Duarte Cancer Center , Duarte, CA 91010,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6578-178X","authenticated-orcid":false,"given":"Eric","family":"Vail","sequence":"additional","affiliation":[{"name":"Cedars-Sinai Medical Center , Los Angeles, CA 90048,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2026,10,16]]},"reference":[{"key":"2026102309415314800_oyag411-B1","doi-asserted-by":"publisher","first-page":"84","DOI":"10.1038\/s41698-025-00876-y","article-title":"Circulating tumor DNA to monitor treatment response in solid tumors and advance precision oncology","volume":"9","author":"Bartolomucci","year":"2025","journal-title":"NPJ Precis Oncol"},{"key":"2026102309415314800_oyag411-B2","doi-asserted-by":"publisher","first-page":"896","DOI":"10.1038\/s41467-018-03215-x","article-title":"Early circulating tumor DNA dynamics and clonal selection with palbociclib and fulvestrant for breast cancer","volume":"9","author":"O\u2019Leary","year":"2018","journal-title":"Nat Commun"},{"key":"2026102309415314800_oyag411-B3","doi-asserted-by":"publisher","first-page":"1296","DOI":"10.1016\/S1470-2045(20)30444-7","article-title":"Circulating tumour DNA analysis to direct therapy in advanced breast cancer (plasmaMATCH): a multicentre, multicohort, phase 2a, platform trial","volume":"21","author":"Turner","year":"2020","journal-title":"Lancet Oncol"},{"key":"2026102309415314800_oyag411-B4","doi-asserted-by":"publisher","first-page":"1367","DOI":"10.1016\/S1470-2045(22)00555-1","article-title":"Switch to fulvestrant and palbociclib versus no switch in advanced breast cancer with rising ESR1 mutation during aromatase inhibitor and palbociclib therapy (PADA-1): a randomised, open-label, multicentre, phase 3 trial","volume":"23","author":"Bidard","year":"2022","journal-title":"Lancet Oncol"},{"key":"2026102309415314800_oyag411-B5","doi-asserted-by":"publisher","first-page":"569","DOI":"10.1056\/NEJMoa2502929","article-title":"First-line camizestrant for emerging ESR1-mutated advanced breast cancer","volume":"393","author":"Bidard","year":"2025","journal-title":"N Engl J Med"},{"key":"2026102309415314800_oyag411-B6","doi-asserted-by":"publisher","first-page":"599","DOI":"10.1007\/s10549-024-07376-w","article-title":"Comprehensive genomic profiling of ESR1, PIK3CA, AKT1, and PTEN in HR(+) HER2(\u2212) metastatic breast cancer: prevalence along treatment course and predictive value for endocrine therapy resistance in real-world practice","volume":"207","author":"Bhave","year":"2024","journal-title":"Breast Cancer Res Treat"},{"key":"2026102309415314800_oyag411-B7","doi-asserted-by":"publisher","first-page":"15","DOI":"10.1038\/s41523-024-00617-7","article-title":"CDK4\/6i-treated HR+\/HER2- breast cancer tumors show higher ESR1 mutation prevalence and more altered genomic landscape","volume":"10","author":"Chaudhary","year":"2024","journal-title":"NPJ Breast Cancer"},{"key":"2026102309415314800_oyag411-B8","doi-asserted-by":"publisher","first-page":"85","DOI":"10.1186\/s13058-021-01462-3","article-title":"ESR1 mutation as an emerging clinical biomarker in metastatic hormone receptor\u2011positive breast cancer","volume":"23","author":"Brett","year":"2021","journal-title":"Breast Cancer Res"},{"key":"2026102309415314800_oyag411-B9","doi-asserted-by":"publisher","first-page":"5169","DOI":"10.3390\/cancers15215169","article-title":"ESR1 gene mutations and liquid biopsy in ER-positive breast cancers: a small step forward, a giant leap for personalization of endocrine therapy?","volume":"15","author":"Betz","year":"2023","journal-title":"Cancers (Basel)"},{"key":"2026102309415314800_oyag411-B10","doi-asserted-by":"crossref","first-page":"107442","DOI":"10.1016\/j.esmoop.2026.107442","article-title":"Emergence of ESR1 mutations (ESR1m) in ctDNA during first-line (1L) endocrine-based therapy in HR+\/HER2\u2212 advanced breast cancer: findings from the SERENA-6 trial","volume":"11","author":"Bidard","year":"2026","journal-title":"ESMO Open"},{"key":"2026102309415314800_oyag411-B11","doi-asserted-by":"publisher","first-page":"3423","DOI":"10.1200\/JCO.23.00638","article-title":"Testing for ESR1 mutations to guide therapy for hormone receptor\u2013positive, human epidermal growth factor receptor 2\u2013negative metastatic breast cancer: ASCO guideline rapid recommendation update","volume":"41","author":"Burstein","year":"2023","journal-title":"J Clin Oncol"},{"key":"2026102309415314800_oyag411-B12","author":"Referenced with Permission from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines\u00ae) for Breast Cancer V.7.2026","year":"2026"},{"key":"2026102309415314800_oyag411-B13","doi-asserted-by":"publisher","first-page":"180","DOI":"10.1016\/j.annonc.2025.10.006","article-title":"Patient-reported outcomes in the SERENA-6 trial of camizestrant plus CDK4\/6 inhibitor in patients with advanced breast cancer and emergent ESR1 mutations during first-line endocrine-based therapy","volume":"37","author":"Mayer","year":"2026","journal-title":"Ann Oncol"},{"key":"2026102309415314800_oyag411-B14","doi-asserted-by":"publisher","first-page":"LBA1007","DOI":"10.1200\/JCO.2026.44.17_suppl.LBA1007","article-title":"First-line (1L) camizestrant (CAMI) for emergent ESR1 mutations (ESR1m) in advanced breast cancer (aBC): final progression-free survival 2 (PFS2) from the phase III SERENA-6 trial","volume":"44","author":"Bidard","year":"2026","journal-title":"J Clin Oncol"},{"key":"2026102309415314800_oyag411-B15","author":"US Food and Drug Administration","year":"2026"},{"key":"2026102309415314800_oyag411-B16","author":"European Medicines Agency. Etcamah","year":"2026"},{"key":"2026102309415314800_oyag411-B17","author":"Pharma Japan"},{"key":"2026102309415314800_oyag411-B18","author":"Etcamah 75 mg Film-Coated Tablets: Summary of Product Characteristics","year":"2026"},{"key":"2026102309415314800_oyag411-B19","doi-asserted-by":"publisher","first-page":"104427","DOI":"10.1016\/j.critrevonc.2024.104427","article-title":"Standardized molecular pathology workflow for ctDNA-based ESR1 testing in HR+\/HER2- metastatic breast cancer","volume":"201","author":"Guerini-Rocco","year":"2024","journal-title":"Crit Rev Oncol Hematol"},{"key":"2026102309415314800_oyag411-B20","doi-asserted-by":"publisher","first-page":"18","DOI":"10.1038\/s41523-026-00894-4","volume":"12","author":"Taranto","year":"2026","journal-title":"Evaluating the Clinical Utility of ctDNA Testing to Identify Molecular Cancer Progression\u2013Lessons from SERENA-6. NPJ Breast Cancer"},{"key":"2026102309415314800_oyag411-B21","doi-asserted-by":"publisher","first-page":"903","DOI":"10.1080\/14737159.2025.2576021","article-title":"ESR1 ctDNA testing: literature review and comparison of assays for ESR1 mutation detection in advanced hormone receptor-positive breast cancer","volume":"25","author":"Yarunin","year":"2025","journal-title":"Expert Rev Mol Diagn"},{"key":"2026102309415314800_oyag411-B22","doi-asserted-by":"publisher","first-page":"80","DOI":"10.1038\/s41523-026-00967-4","article-title":"SERENA-6 interpretation and clinical implications: intercepting endocrine resistance in metastatic breast cancer","volume":"12","author":"Bidard","year":"2026","journal-title":"NPJ Breast Cancer"}],"container-title":["The Oncologist"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/academic.oup.com\/oncolo\/advance-article-pdf\/doi\/10.1093\/oncolo\/oyag411\/72033741\/oyag411.pdf","content-type":"application\/pdf","content-version":"am","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/oncolo\/article-pdf\/31\/11\/oyag411\/72033741\/oyag411.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/oncolo\/article-pdf\/31\/11\/oyag411\/72033741\/oyag411.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T13:41:56Z","timestamp":1792762916000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/oncolo\/article\/doi\/10.1093\/oncolo\/oyag411\/8931032"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,10,7]]},"references-count":22,"journal-issue":{"issue":"11","published-print":{"date-parts":[[2026,10,7]]}},"URL":"https:\/\/doi.org\/10.1093\/oncolo\/oyag411","relation":{},"ISSN":["1083-7159","1549-490X"],"issn-type":[{"value":"1083-7159","type":"print"},{"value":"1549-490X","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2026,11]]},"published":{"date-parts":[[2026,10,7]]},"article-number":"oyag411"}}